Sulfidation of minerals



May 13, 1952 H. A. SHABAKER 2,596,609

SULFIDATION oF MINERALS Filed Feb. 5, 1948 :inventor HUBERT H. EHHBHKEH Cftorneg Patented May 13, 1952 SULFIDATION OF MINERALS Hubert A. Shabaker, Media, Pa., assignor to Houdry Process Corporation, Wilmington, Del., a corporation of Delaware Application February 6, 1948, Serial No. 6,722 19 Claims. (Cl. 23110) The present invention relates to improved methods for suldation of materials such as minerals. It is particularly concerned with the preparation of improved clay products by methods including suliidation, especially when followed by removal of iron suldes thus formed, obtaining modified clay masses particularly useful as catalysts in hydrocarbon conversion processes.

In copending applications Serial No. 644,423, led January 30, 1946, and 681,426, filed July 3, 1946. (filed jointly in the names of myself, George Alexander Mills and Ruth C. Denison) now issued respectively as Patents Nos. 2,466,048 and 2,466,052, issued April `5, 1949, methods are described for the production of modified clay masses providing catalysts of unique properties, by treatment of iron-containing clays with sul riding gases at elevated temperature followed by the removal of the iron sulfide thus formed. The novel contact masses thus obtained are changed in physical and chemical properties and demonstrate important advantages as catalysts, including exceptional stability in cracking or treating petroleum stocks of high sulfur content.

In my copending application Serial No. 774,439, iiled September 16, 1947, now Patent No. 2,561,442, issued July 24, 1951, certain improved methods for suldation of clay are described, employing a hot gaseous carrier medium for dilution of the active sulding gas and providing the necessary heat for bringing the clay to required temperature for suldation.

By the present invention further improvements in the suliidation procedure are obtained, affording important advantages of enhanced emciency and economy of operation, which improvements are adapted to commercial utilization for the large scale production of modified clay products of uniformly good quality.

In accordance with the present invention the sulfldation of an iron-containing clay or other mineral is carried out in at least two stages, wherein in an initial stage the clay or mineral is heated to desired high temperature by contact with an' essentially inert gaseous medium carrying a comparatively small quantity of active gaseous sulfide, such as HzS or CS2, and the thereby heated and partially suliided clay then contacted for a short time with concentrated sulfiding gas to perfect or assure completion of the sulding reaction. The sulded clay is subsequently cooled and subjected to acid-leaching, principally eiecting thereby removal of the iron suldes formed. By this operation complete and uniform sulding of the clay is obtained using only fairly small amounts of active suliiding gas for reaction with the iron content of the clay, aifording, among other advantages, the best economy in the use of the suliiding gas. The resulting sulfided clays are capable of being easily leached with acid to provide modified clay products of low iron content and of uniformly high and stable catalytic activity.

The process of the invention may be operated simply as a batch method by employing a suitable reaction chamber for retaining the clay and providing the chamber with means for introducing streams of gases of different composition or concentration under manual or automatic control. or if desired one or the other of the treating stages may be applied as a continuous operation. For instance the clay may be passed through a primary heating and treating zone and discharged into one or more receptacles wherein the second stage treatment is carried out batchwise.

It is preferred, however, in commercial operation, to employ a completely continuous process, such as a system wherein the catalyst moves counter to the treating gas through the several treating stages. Thus, a heated carrier gas may be admitted into the reactor containing a moving bed of clay at a location in the system ahead of the point of entry of the sulding gas, thereby providing a period during which the clay is initially heated by contact with the gas to desired reaction temperature. During this period the clay is in contact with hot gas of low sulfide concentration, as will be described, and the thus sulded or partly sulded clay is then contacted for a short period as it moves through the reactor with the more highly concentrated sulfiding gas completing the sulfldation of any unsulded portions thereof. Examples of various embodiments and particular forms of apparatus of the continuous type that may be employed in carrying out the multistage sulfidation described, are disclosed in my copending Vappli-f cation Serial No. 6,683 filed of even date herewith. For convenience, details of operation of the present method are hereinafter described with reference to the accompanying drawings, illustrating one type of continuous apparatus that can be employed in practice of the invention.

In accordance with the improved process` of the present invention, the clay is heated up to required temperature and most, if not all, of the iron is reacted in the first stage during contact might be experienced during operation of the previous stage. Such irregularities inv operation during the first stage may result from gas channelling, imperfect mixing of non-uniform mixtures of active sulfide and carrier gas, nonuniformity of timeof contact due to differences' in iiow rate of the clay over thecross sectional., area of the reactor, or other conditions thatY might be encountered in practical operation.

The described two stagev treatment, in addition, results in important econom.es in heating costs andA ini total. sulding gas. During, the..initial heating stage smallamounts of sulfide gas mayL Y be used, evenlless .than theoretically required. for

complete suldation. The required reaction can then be easily completed with high concentra-l tions-of sulfide gas in'a comparatively low bulk volume;v The sulfding reaction isA apparently endothermic, andit is therefore advantageous to Y effect at least an appreciable part ofthe reaction in the presence Yof theheatinggas.

Formation of detrimental. products. of suliidation, if any, takes place at theY upper portionof the reactor in the. region of; lowest temperatures` and inthepresence of large volumes of gas. serving to viiush these detrimental productsfrom thereactor, thereby minimizing any undesired effects onv the sulii'ded clay.

The accompanying drawings which are largely diagrammatic, illustrate one type of continuous treater adapted' for use in practice of the invention, wherein Figure 1 is a view in elevation, with Vparts of the wallbroken away to show the construction thereof and portions of the interior of the apparatusshown inv cross-section; Figure 2 is a-horizontal,cross-section thereof taken along the line 2 2 of Figure 1; Figure 3 is a horizontal cross-,section of the lower portion of the reactor taken online 3--3` of Figure l; Figure 4 is a partialview illustrating a modied -form of grid. wall that may be substitutedin the reactor of Figure 1; and Figure 5Y is a horizontal cross-section thereof taken along the line -Srof Figure 4.

Referringinow particularlyto Figure 1, thereis shown generally a treater or reactor I, whichis preferably cylindrical at its upper section formed` by the perimetric wall 2, which may be con.- structed of any suitable material. Since the tem-V perature ofsulfide gas in Ythis section isv quite high, a refractory lining of the inner walls is provided as shown at 3; this lining should be employed at least at those parts of the reactor wall coming into contact with high temperatureV sulfide gas. The clay is introduced at the top of j the reactor by any suitable means, such as. a hopper 4', supplied by a chute, moving conveyor, or other means (not shown). From the hopper, the clay passes downwardly by gravity as a moving bed through the reactor entering a zoneV of narrowed cross-section at and below the distributing mem-ber 5, by passing' through distributing down-comers 6 formed or inserted in that member, also preferably made of material, such as'ceramic, resistant to corrosive gases.

Heating gasV is introduced through a supply pipe'l (Figure 2) entering through thewall of" the reactor and terminating at a circumferential channel 8 formed in the liner'3. The supply pipe I is substantially tangential to the channel so as to impart a swirling action to the gas introduced. The inside wall of the liner 3 over a portion of the longitudinal extent of the channel is provided with a grillworl; or grid section furnishing suitable openings 9 for admission of the gas into the reactor, such as by means of horizontally or vertically disposed slots, or reticulated or perforated grids. By the construction shown, the hot gas in the circumferential channel 3 serves to maintain the mineral particles being heated at their attained temperature without heat loss through the wall'.

' At the discharge end of the reactor I, means are provided forV introduction of theconcentrated sulde gas, entering through a supply line I and passing upwardly, in counter-current relation to the moving clay particles, through the downcomers 6A into the main chamber of the reactor.

To prevent. discharge of sulfide gas, with the clay,I

In theem-bodiment illustrated in 1Figures 4 and.

5, the grid section instead of being integral as in Figure11, is shown as formed of spaced tiles I3',

providing openings therebetween for, admission of the heatinggas, similarly to the openings Sof.

Figure` 1.

As` the sulde gas introduced through line .Ie passes upwardly it comes into contact and isad`-4 mixed with the hot gas introduced through thev openings e in the grid wall (orV through the spaces between the tiles I3) The hot gas being introduced at a rate and pressure causing horizontal movement toward the'center of the reactor and being forced upwardly by the positive movement of the active sulding gas entering through the passages good mixing of the gas can thus be obtained Vto provide a quite uniform dilute sulfide gas forrheating and eifecting initial sulfid-YV ing of thel clay. The spent gases may bewithdrawnpthrough a suitable discharge line such as i is shown at I2', to waste, or may bezrecoveredv for reuse in this,- process or for other industrial.

purposes.

In the construction of: the apparatus. illustrated, -or other types of apparatusv that maybe substituted, provision is thus made for securingf the desired, mixture of sulding gas and heated. carrier gas constituting the dilutetreating gasv for the irst stage treatment, asa result of the iiow or diffusion of a portion of the concentrated sulfide gas from the later treating stage; theconstruct-ion being such as tominimize channelling. It is preferred in' practice, however, toV further assure suldation of the clay" throughout the;v cross-section of the reactor, to add at least a` small portion; of suliidefgasY with'thexcarrier gas.

directly introduced into the reactor in thefrst` stage; for example, by. admission-of; the carrier gas together with the desired portion'vof sulfiding.-

n gas through line 'I in the illustrated apparatus.

perature as a result of the first' stage treatment;

and only small amounts of total 'gas and a comparatively short time is employed for the second stage, ordinary temperature may be employed including room temperature or lower. In fact, reduction in temperature of the clay during the second stage suldation treatment may be advantageous from the standpoint of cooling, which is necessary before the sulded clay can be leached.

The heating gas serving also as the carrier gas for the dilution of the I-IzS or CS2 particularly for use in the first stage of the treatment of the clay must be essentially inert; that is, it must be free from oxidizing constituents which would consume the active suliiding gas, and also free from other constituents in amounts which would interfere with the sulfldation reaction or be harmful to the catalyst. Commercial nitrogen is an lexample of a gas substantially fulfilling these requirements.

Another essentially inert heat carrier gas, which is comparatively cheap and readily made available, is a specially processed or prepared flue gas, which may be obtained for instance by the controlled combustion of a fuel. Gaseous fuels are preferred because of easier control of combustion; examples of such gaseous fuels which may be burned to provide ue gas, include propane, and domestic heating gas.` Such iiue gases from commercial propane, for instance. can be readily prepared free of oxygen, but would then contain components such as water vapor, CO2. and generally small amounts of CO and Hz in addition to nitrogen. In the case of the single step process of sulding clays with diluted sulfide gas as described in my copending application Serial No. 774,439, the quantity of carbon dioxide that may be present in the treating gas is limited because of the adverse effect of large quantities of carbon dioxide on the sulfidation reaction and on the `'subsequent acid leaching of the clay. As therein described, in the use of such iiue gas, the carbon dioxide content can be substantially eliminated or reduced to practically non-interfering concentrations by caustic wash or by treatment with amines. The adverse effect of large quantities of CO2 in the order of 10 to 15% by volume of the carrier gas, moreover, can be largely counteracted by using larger concentrations of active sulfide gas in the carrier gas than the theoretical equivalent required to react'with the iron content of the clay, preferably 3 to f1 or more times the calculated equivalent.

In following the two-stage treatment of the i more (by volume) CO2 and only very small concentrations of sulfide gas, in the order of 0.5% to 1% HzS (of the total volume of treating gas), followed by a short treatment of the clay in more concentrated sulfide gas, preferably about to 50% by volume of the treating gas; the total quantity of sulfide employed, need be only slightly in excess of the theoretical equivalent of the iron content of the clay.

During the first stage treatment wherein the clay is being heated to desired temperature. comparatively large amounts of treating gas are required. Under practical counter-current heating conditions, it has been found that about 1000 to 1300 volumes of flue gas are required to heat 1 concentration for the volume of clay (such as an acid-activated subbentonite weighing lbs. per cu. ft.) from room temperature to 1400 F., the time required depending upon the rate at which the gas is admitted. The rate of admission of the heating gas has no noticeable effect on the sulfidation reaction, provided itis high enough to heat the clay to desired reaction temperature. L After the clay has been heated to the desired temperature for sulfidation. only about a half hour or less may be required for obtaining complete reaction with the iron content of the clay;' nevertheless it will be found advantageous to retain the'clay at the attained temperature for at least 1 hour and preferably for about 2 to 5 hours before subjecting the clay to subsequent treatment with the concentrated suliiding gas. Extending the time of treatment beyond the indicated time has not been found of any particular advantage; nox-,on the other hand has any detrimental effect been noted.

During the later stage cleanup" treatment l5 to 100% by volume concentrations of gaseous sulfide, such as CS2 or HzS. may be employed; concentrations of from 25 to 50% being preferred. The treatment with the concentrated sulfide gas in the second stage need be conducted for only a comparatively short time, as several minutes; even with low concentrations of sulfide of the order of 10 to 15%, 10 to 30 minutes have been found quite satisfactory.

The carrier gas for the concentrated sulfide treatment, of course, may be of the same or different composition than that employed. as heating gas in the first stage; for simplicity of practical operation, however, it is preferred to employ the same carrier gas. In employing the continuous process of the type illustrated. dilution of the 100% or other concentrations of hydrogen sulfide gas introduced through line l0, is obtained by adjusting the rate and volume of seal gas introduced through line ll, so that rthe upwardly directed portion will admix with the hydrogen sulfide to furnish the desired. ultimate cleanup treatment. Thus, the upwardly flowing portion of the seal gas joined by one-third to equal volumes of 'sulde gas will form a combined gas stream of 25 to sulfide concentration for the cleanup operation.

To obtain good suliiding action and ready removal'iby mild acid leaching ofthe formed iron sulfide, the treating gases should be substantially free from uncombined oxygen and from water. A maximum moisture content of 0.02 volume percent of the described iiue gas used as vdiluent and heating gas is readily obtained by v moderately reducing gas (containing 6.4% CO,

4.0% H2, 9.8% CO2). Upon heating of a gas containing COz and H2 to temperatures in the order of 1200-1400 F., a water gas reaction can oc- .acid-activated sub-bentonite Enron In the tprefertedzoperation of the .continuous .process described, `the1 concentrated sulde gas from :the'ftpleanupl' section was permitted -to ene ter. fthe main tneating .section -fornse ftherein. It will .be apparent, that :if desired, .this @as may aloe` vented. `the reactor, and ail ,of the desired concentnation .of .sulde gas .separatelyl 'tarnished foraheJ-first-.stage treatment.

. rios. lofriinsiofbatch ooortiooa. o gaseous Lixtorfe having the oomoositioo ofV o petadilij prepared fluo gfa was "employed oon-- 25, one@ oo, and amont.11.5%.Con4 'remainder 'being' .inert vgas om .Soo moet .Mindy o? 1&2-, To tli. oootpoitioo. .moll amounts. of hydrogen lode i et .oompositionzas .in the lrst; stage. for gperioos orA to, 15 minutes.. e

V'I ,o aytreated `.waa a pelleted commercial taining iron V(2,1% Fe2f(,f 3).` In al1. instances after acid 'leaching' r:the .sulded .clay with .dilute oooouls. HC1 .(15% cono.) for y24: .hours at 'room temperature, catalyst pellets. .of'farly 'uniform color, of 'accpiably low 'x'..elsrichlal iron content, andhaving good catalytic Yproperties were obtojiood.- T-.hoeotivi-Wof; the catalyst was tested by the. -QfI 3-A ntethod 'described by H. J. AA1.-

exandelj and. Shimp National lPetroleum 4 Nw,L tochoiool Section, .August .2, 1944.. pp. @537.1% Y

commencial acid-'activated montmorillonite. .eayl

percent .CS2 at 1400:o i'. :011 i5k -honrs in the 1st stage. followed tby..a `15 minime treatmentwlth thesarnecarrier gas containing :about :3Q-.131 vol. percent Csnand room temperature Aacid loathe. ing. 4as before, .catalysts were-.obtained .of ,less than .0.2% :residual flfezOazand having an aotivity by the CAT-A method of 378-41 volume percent. gasoline.

*The quantity.. .of sulfide;stoioniometricalltrtfV quired to react wthlthe iron .content Aof clay.

amounting toa-bout .tions thoorotoai requitomont accordance with. the. above o llf tiono) tem, lfatnres ranging; from about 13.59@ about .14.50 lots@ voxieo'con.- ditiooo included .the iotrqduotioo of al. 0f; oro-roseo. .s ude. Vused tomo leonor ootion ata oon. .ra -thorooootofaoy-Yol: u moj of total. ...goo and. oo ti. ng about 2l5 tho. theoretical .regu-romeo ogwolll. as". the ntrodootion of a portionor he hydrogen sul'- fido nireetlywito. the toting o .nt gnam .com centrati@ s .jigom about 0,7`5 ,tol 'Z5 Qf thtotal Yt.-Ifltroo-in;ed '1J-he cIays'treated in ...doothooorom-eoio1ooili C cioe .-moritmorllqlt ceding oxaropl o ocio-activated o' ilo my" routed tofpenets. of

0 high density (6.70 lgg/lt). 'lhecalcined .a5 Well as thounoaloiood. oloy Wolfe. equally Welllfsudodf Percent' 4`CS'zwa-s substitute@ `for `Hgsdn a flue gas composition Vsuch as that' described -in the preceding example. Treatment -of another sample of a Other continuous treater runs made with wider variation of the flue gas employed, (e. g. 9.8% CO2, 4.0% H2 and 6.4% CO by volume) as well as by addition of up to H2 lto the gas in the cleanup section, showed similar results, obtaining clay residues of less than 0.1%V FegOa showing activity of approximately by volume gasoline by the CAT-A method. Use of a ue gas containing 0.6% oxygen and free from H2 and CO (13.8% CO2) produced catalysts of above.

40% gasoline activity and containing about 0.11% FezOa; there was evidence, however, of some exothermic reaction. In several runs using undried flue gas containing up to 2.6% H2O by volume, the residual iron after acid leaching was somewhat higher being between 0.15 to about 0.20% FezOs; the CAT-A gasoline activity was not noticeably affected.

By the two stage operation employing fairly dilute sulfide gas in the first stage, in addition to the advantages already set forth, al1 oi the advantages of dilute suliide gas over the use of 100% sulfide gas (or highly concentrated sulfide gas) are retained, including greater facility of complete removal of freed iron by room temperature acid leaching, more economic use of expensive sulde gas, minimization of corrosion by concentrated suldes, better uniformity of suldation, etc. Lower concentrations of sulfide gas in the first stage and less total quantity of sulde can be employed, moreover, `than are required for best quality products obtained in a one-stage operation with'dilute sulde gas. The nal cleanup with a small` volume of concentrated sulfide for a short `time assures uniform and complete suldationand permits reduction in total sulde employed as 4well asin the total treating time required in a one-stage operation with comparative results.

It was also found in using the described twostage operation that lower treating temperatures could be employed to effect equivalent sulfidation than in a one-stage operation with substantially equal iron removal `by subsequent acid leaching. With the type of clay of the above4 example, although lower temperatures can be used, nevertheless, catalysts of lowest residual iron and maximum activity are obtained with sulfidation at about l350-1400 F. The content of CO and H2 as well as CO2 in a flue gas carrier has a less marked influence on suldation by the described two-stage treatment than in a one-stage treatment with dilute sulfiding gas.

The results obtained with treatments made on sub-bentonite and other clays of various oririn indicate the general applicability of the described process and conditions of operation. Although there were individual variations, it was found that reasonably low residual iron in the modified clay could be readily obtained under the conditions given; in some instances this may necessitate more drastic treatment than in the case of the illustrated clay, as by the employment of the longer treating time, to about 5 hours, and/or somewhat higher concentrations of sulfide in the rst stage operation as up to 3 to 5% of the treating gas or 4 to 6 times theiron equivalent of the clay. A

Obviously many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof and therefore only such limitations should be imposed as are indicated in the appended claims. i

I claim as my invention:

1. The process of sulfiding solid mineral material containing components reactive Vto form metallic suldes, which comprises initially heating such a mineral'material by contact with comparatively large volumes of a treating gas introduced into; a primary treating zone, said gas being composed of a preheated essentially inert carrier gas containinggaseous sulde inl dilute concentration therein, maintaining contact between said mineral material and said treating gas in said primary treating zone for a period at least sufficient to heat said mineral material to desired reaction temperature and simultaneously effecting thereby the initial sulfidation of said reactive components, and thereafter contacting the thus heated material with a comparatively small volume of concentrated sulfiding gas for a controlled period in a subsequent Vtreating zone' by introduction of said concentrated sulding gas into said subsequent treating zone under indegen sulde in a weight ratio to the iron` content 'of the clay .of from about 0.8 toabout 1.6.

4. The process in accordance with claim 2 wherein the iron content of the clay is subsequently removed by mild acid leaching to provide a modified clay product of low iron content and improved catalytic property. e

5. The process in accordance with claim 2 wherein said heated treating gas contains about 0.7% to 2.1% of hydrogen sulfide by volume and `said concentrated sulfiding gas contains 15 to 50% by volume of hydrogen sulde. t

6. The .process in accordance with claim wherein said treatment with concentrated sulding gas is effected in 5 to 15 minutes.

7. The process in accordance with claim 1 wherein the contacting of said mineral maierial with the heated treating gas and with said concentrated gaseous sulde as defined is effected by a continuous process wherein said mineral material is continuously passed as a moving bed through a plurality of treating Zones countercurrent to the respective treating gases aforesaid moving through said zones.

8. The process in accordance with claim 7 wherein said heated treating gas is introduced at a temperature and permitted to contact said mineral for a time sufficient to heat said mineral material to at least 1350 F.

9. The process in accordance with claim 8 wherein said heated treating gas is retained in counter-current contact with the moving bed of mineral material at said recited minimum temperature for about one-half hour to over 5 hours.

10. The process of treating iron-containing 4clay with gaseous sulde at elevated temperature to convert the iron present therein to iron sulde,

. which comprises passing a solid moving bed of said clay through a primary treating zone in counter-current contact withheated dilute sulfide gas introduced intofsaid'zone ata temper- Yature Yand" maintained in-"contacti' with f the clay for' atirnef sufficient" to heat' theclay tol desired suliiding `temperature -by direct heat exchange therewith, thereby effecting; initial and at least partial' sulfi'dation; ofthe'ircn content of said an;essenti ally inertcarrier gas' containing fagaseous; sulde in dilute. "concentrationY therein ;v contiruiouslyv withdrawing; the thusV heatedb andI sul- :iidedj '012133:,IQIIITsaid"primary treating; zone into a .subsequent.ttreating'zone oreduced crossV sectipn introducing concentrated gaseous; suliide into said" suhsequen'vz'tlieatine Zone ata Voreillettetzure lowerthenthatr oftheA olarentering; Said V zone andfcontactingjthej hotcl'ay insa-id latter zene withA saidgcooler 'gaseous' sulfide'to 'complete and nerfectthe isuldation offanyincompletely reacted; irongthereim and discharging the 'thus 1 1; The process-tin 'accordance with; claim 10 whereinjsaidj heatelddi'lute sulfide gas containsfas .active s uliiding` constituent an amount of hydrogensuliideseveral times in excess of the theoretical` requirement ior'complete suld'ation'of the iron contentoftheclay.' Y

12.1"111el process in accordance withV claim 10 wherein said', heateddilute sulfide gas is` com-V posed predominantly 'of' nitrogen and contains up to. 15% by-volume carbon'dioxiie and' small quantitiesjofv carbon monoxide'andhydrogen not in excess of 4% by volumeo tlietotalj gas..

13. The: process in, accordance "with claim l() wherein; saidV clay isV heated msaidprimary treat- 14.*,"The process: in accordance; with; "claim, 10 whereinsaidheated dilute sulde 'eas-employed inisaidrnrimary treating,4 zone'is formed', byjadiducejct into Ysaid zone.' with concentrated 'su-Inde gasy previously contacted" with hot clay insaid zone of reduced cross-section.

"1,52 'Thei'process accordance-withclaim leV Whereinsaid heated" carrier Agas directly intro- .duced'in said primary treating*v zone 'is composed of an essentially 'inert 'gas 'Containing up to` 2% ofv hydrogen suld'e.I

116. The process 'or' suliidingv "at elevated temperature solid@mineral"materlarcontaining components reactive to form metallicsuldesywhich comprises continuouslyintroducing such mineral material into a heating andY primary treating Zone t0 form. a continuous `downwardly moving Vbell in said)'z one,4 passing themineral materials vfrom said'zone to a second"zonej'constituting a concentrated'treatingzone, maintainingthe mineral' material' in said concentrated treating zone as a moving mass for a comparatively short period of time, discharging the treated4 mineral materialiromV said second zone downwardlyY as a continuous column of narrow cross-section, in-V treating zone-heatedzdi1uent gas'at a tempera-1 fture not yless thanfthe desiredfjreactionitemperature, ysaid idiluentgas 'consisting 'offan `essentially 'inertV carrier gas contain-ingfafsmall amount oif gaseous gsuliide; admitting thef admixed gases; from'-saidf,concentratedtreatingzone into'v-said'primary zone and diffusing theisame'in v`ad-mii'rture with the heated` di-luentVv gas." ldirectly introduced* thcrein toV forma f hot diluted-1 heetingandV prima-ryl treating gas, mixture iicwing upwardlyv through saidj primary treating zonein counter-current contact with thedownwardly moving; bed off" mineralA material Vin saidffzone, disengaging spentV gases-from said? mineral material; above: said primarytreatingf 'zoneand` discharging the same;` discharging the su-Ifided mineralmaterial from said continuous column-cf vnarrow* cross-section; said seal; gas 'preventing discharge of sulfide gas witii'sai-dmineralmatetrial.`

17: The processy of improvingl thefpropertiesof 'acid-activated sub-bentonite clays containing iron compoundsnot removedI duringacid-l activation, which Vcomprises passing sucira clay inthe form of agglomeratedmasses downwardlyasfa continuouslyv moving bed through afl-'ieating and primary treating zone; contacting themoving bed ofgclay in said zone with heatedtreating 'ga-s, said gas being cor-moosed'ofL an essentially inert carrierv gas7 and-hydrogen sulfide inav concentratotal heated `treating- 'ga-s,l thelieated treating vgas being-at af suiciently high temperature and being introduced' in suicientlly largevolume'to 'eif'ect `heatingl ofi the clay 'td-at 'least T3509: F. l 'and' nc'ztfabove 14509-112, withinv said heating; 'and primary treatingl zone;4 passing the thusheated s and at least partially sulfidesl clay into a cleanup zone in;- counter-eurrent lcontac-t'with-f a comparatively small` volume of'fconcentratedfsu1fid ing*y gastoassuref-complete suliidationfoif the iron content; offthe' clay; said? concentrated sul'ding gas' beingat `a` temperaturek lower' thanI that of the l clay passed into said?.clean-'upzone' and" containing at least 25% -byvclume-Ihydrogen sulfide,

' furtherl coolingI thethuszsuliidedVv clay, andi-thereafter acidi leachingv theccoledv clay-5to removeiron sulfides formed-therein;

18'. The process of Isul'i'idingfgranularclaycontaining-components' reactive to form metallic sul fides; which comprises/passingsaid `clayi-d`ownwardly as a continuousA moving-bed'fthroug-h a path= constituting a heating and primaryv `treatingY zone'y and thence for a comparatively shorter timethrough a path constituting a concentrated treating zone,l introducing *concentratedl sulfide gas into the; latter; zonee atY a'xlowl volumetric rate, fflowing: said.' concentratedgas upwardiy and in -countercurrentcontact with the clay; passing Ythrough said; concentrated treating zoneto assure and perfect the completion of thev suli'ldation reactionv initiatedI in. said primary treating zone, directlyY introducing into said` primary treating zone hotY diluentgascomposedj predominantly of inertlconstitu'ents toeiect, heatingof said clay in.. saidjprimary Vtreating zone to` 'desired temperature, said concentrated sulfide gas admixing with said' hot' 'diluent gas in saidfpri- *mary treating' zone' and `the admixturethus formedr owing upwardly through saidl primary treating zone asa dilutedsuliiding :gaseifectingheating of' said clay byy directheat'exchangein counter4 current contact, therewith: and initiating vated temperature; said vhot diluent gas` being introduced into said primary treatingzonerover a Wide area providing obstructions to now thereby effecting diiusion of said gas through the moving bed of cla-y in said zone and minimizing localized channeling or" the gas; discharging spent gases above said primary treating zone and discharging tlie thus sulded clay below said concentrated treating zone.

19. The process in accordance with claim i8 wherein said hot diluent gas is introduced into said primary treating zone, by providing a oontinuous layer of said gas oircun'iierentially sur rounding said moving bed of clay in said zone along a substantial portion of the longitudinal extent of said bed, and directing said surrounding gas inwardly in a multiplicity of paths over l said area providing obstructions to flow.

HUBERT A. SHABAKER.

CITED The following references are o record in the ie of this patent:

UNITED STATES PATElBlTS Number Name Date 1,368,396 Hulett Feb. l5, 192i 1,727,441 Parentani Sept. 10i, 1929 1,816,842 Haglund Aug. 4, 193i 2,388,302 Weyl NOV. G, 1945 2,466,046 Shabaker Apr. 5, 1949 2,455,047 Shabaker Apr. 5, 1949 2,466,048 Shabaker Apr. 5 1949 2,528,553 Royster Nov. 7, 1950 2,533,142 Royster Deo. 5, 1950 

1. THE PROCESS OF SULFIDING SOLID MINERAL MATERIAL CONTAINING COMPONENTS REACTIVE TO FORM METALLIC SULFIDES, WHICH COMPRISES INITIALLY HEATING SUCH A MINERAL MATERIAL BY CONTACT WITH COMPARATIVELY LARGE VOLUMES OF A TREATING GAS INTRODUCED INTO A PRIMARY TREATING ZONE, SAID GAS BEING COMPOSED OF A PREHEATED ESSENTIALLY INERT CARRIER GAS CONTAINING GASEOUS SULFIDE IN DILUTE CONCENTRATION THEREIN, MAINTAINING CONTACT BETWEEN SAID MINERAL MATERIAL AND SAID TREATING GAS IN SAID PRIMARY TREATING ZONE FOR A PERIOD AT LEAST SUFFICIENT TO HEAT SAID MINERAL MATERIAL TO DESIRED REACTION TEMPERATURE AND SIMULTANEOUSLY EFFECTING THEREBY THE INITIAL SULFIDATION OF SAID REACTIVE COMPONENTS, AND THEREAFTER CONTACTING THE THUS HEATED MATERIAL WITH A COMPARATIVELY SMALL VOLUME OF CONCENTRATED SULFIDING GAS FOR A CONTROLLED PERIOD IN A SUBSEQUENT TREATING ZONE BY INTRODUCTION OF SAID CONCENTRATED SULFIDING GAS INTO AND SUBSEQUENT TREATING ZONE UNDER INDEPENDENTLY CONTROLLED CONDITIONS AND AT A TEMPERATURE LOWER THAN THAT OF THE MINERAL MATERIAL INTRODUCED IN SAID SUBSEQUENT ZONE THEREBY 